Tag: physics

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Questions Related to physics

Multiple choice physics universe and space xx radio telescope and space telescopes optical instruments : telescope

The Hubble Space Telescope is designed with ____________  hyperbolic mirrors is known for good imaging performance over a wide field of view. 

  1. two

  2. four

  3. three

  4. many
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Hubble space telescope is reflecting telescope it is designed with TWO hyperbolic mirrors. A curved primary mirror is the basic optical element that creates an image at the focal plane. And secondary mirror was added to modify the optical characteristics for visual observation.

Multiple choice physics universe and space xx radio telescope and space telescopes optical instruments : telescope

Which among the following is not true for Hubble ST?

  1. Hubbles observations found that black holes are common to the centers of all galaxies.

  2. Hubble's Telescope was first to found the traces of water on Earth.

  3. Hubble Deep field and Hubble Ultra Deep Field images reveal galaxies that are billions of light-years away.

  4. Astronauts used the telescope to observe distant supernovae.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

We know that Earth has water, blue planet, 71% of Earth's surface is covered in water. Hubble telescope was definitely not the first to found the traces of water on Earth. 

Multiple choice physics observing space: telescopes xx radio telescope and space telescopes optical instruments : telescope

An observer looks at a distant tree of height 10 m with a telescope of magnifying power of 20. To the observer the tree appears:

  1. 10 times taller .

  2. 10 times nearer .

  3. 20 times taller .

  4. 20 times nearer .
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Magnifying power of a telescope relates to the angular magnification. It makes the object appear closer by a factor equal to the magnifying power, effectively reducing the perceived distance.

Multiple choice physics option c: imaging xx radio telescope and space telescopes optical instruments : telescope

The focal length of objective and eye-piece of a telescope are $200\ cm$ and $5\ cm$ respectively. Final image is formed at least distance of distinct vision. The magnification of telescope is

  1. $20$
  2. $24$
  3. $30$
  4. $48$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

For a telescope where the final image is at the least distance of distinct vision (D = 25 cm), the magnification M = f_o / f_e * (1 + f_e / D). Plugging in f_o = 200, f_e = 5, and D = 25 gives M = (200/5) * (1 + 5/25) = 40 * 1.2 = 48.

Multiple choice physics logarithms introduction to logarithm logarithmic notation exponential and logarithms

If $\log\ (-2x)=2\log\ (x+1)$, then $x$ can be  equal to

  1. $-2+\sqrt {3}$
  2. $-4+2\sqrt {3}$
  3. $-2-\sqrt {3}$
  4. $-4-2\sqrt {3}$
Reveal answer Fill a bubble to check yourself
A,C Correct answer
Explanation

We have,

$ \log \left( -2x \right)=2\log \left( x+1 \right) $

$ \Rightarrow \log \left( -2x \right)=\log {{\left( x+1 \right)}^{2}} $


Comparing both side and we get,

$ -2x={{\left( x+1 \right)}^{2}} $

$ \Rightarrow -2x={{x}^{2}}+1+2x $

$ \Rightarrow {{x}^{2}}+4x+1=0 $


Using quadratic formula and we get,

$ x=\dfrac{-4\pm \sqrt{16-4\times 1\times 1}}{2\times 1} $

$ x=\dfrac{-4\pm \sqrt{12}}{2} $

$ x=\dfrac{-4\pm \sqrt{2\times 2\times 3}}{2} $

$ x=\dfrac{-4\pm 2\sqrt{3}}{2} $

$ x=-2\pm \sqrt{3} $


Hence, this is the answer.